What is the difference between Exd IIB T4 and Exd IIC T4 in the explosion-proof level identification? The difference between Ex (ia) IIC T4 and Exd IIB T4 is naturally due to the higher level of IIC.

Ex - Explosion proof abbreviation, explosion-proof label d - Explosion proof form, "d" refers to explosion-proof type, can be installed in Zone 1-2 IA intrinsic safety explosion-proof methods, can be installed in Zone 0-2 IIC - Explosion proof classification, mainly divided into Class I (mining) and Class II (factory). Among them, Class II is further divided into IIA, IIB, and IIC (A

1. The basic principle of explosion prevention is that a substance undergoes a physical or chemical change from one state to another, and releases enormous energy. The energy released at a rapid speed will cause violent impacts and damage to surrounding objects. Concept of explosion: ○ 21) Explosive substances

Quality: Substances that can react with oxygen (air), including gases, liquids, and solids. (Gas: hydrogen, acetylene, methane, etc.; Liquid: alcohol, gasoline; Solid: dust, fiber dust, etc.) The three conditions that must be met for explosion: 2) Oxygen: air. 3) Sources of ignition: including open flames, electrical sparks, mechanical sparks, electrostatic sparks, high temperatures, chemical reactions, light energy, etc.

2. Why explosion-proof: Explosive substances: Many production sites produce certain flammable substances. About two-thirds of the underground coal mines contain explosive substances; In the chemical industry, over 80% of production workshop areas contain explosive substances. Oxygen: Oxygen in the air is ubiquitous. Ignite source: Electrical instruments are widely used in the production process, and various frictional sparks, mechanical wear sparks, electrostatic sparks, high temperatures, etc. are inevitable, especially when instrument and electrical failures occur. Objectively, many industrial sites meet explosion conditions. When the mixture concentration of explosive substances and oxygen is within the explosive limit range, if there is an explosive source, an explosion will occur. Therefore, it is necessary to adopt explosion-proof measures.